problem tofu 13c and static dhcp

I recently upgraded from my tofu11 to 13c and found that I no longer can change or add new static dhcp entries (based on MAC). I kept pressing Add but nothing happens. So now I had to disable DHCP server and just manually setup ips on my machines. However this is bit cumbersome. Just wondering if anyone here ran into the same problem or tofu13 has changed something to make setting up static dhcp different now.